The invention relates to a plasma burner comprising a fluid-cooled anode and a cathode, wherein an arc can be produced between the cathode and the anode in a combustion chamber and a burner gas can be passed through the combustion chamber to form the plasma.
Plasma burners of this type are known from the state of the art. They are used, for example, in coating systems. They are normally made from brazable non-ferrous metals and particularly brass (except the electrodes). Hence they have a correspondingly high weight, which leads to drawbacks in their use.
The problem of the invention is therefore to provide a plasma burner with the above-mentioned features, which can be made cost-effectively and used universally.
In the plasma burner according to the invention with the above-mentioned features the problem is solved, in that the plasma burner has coolant passages for applying coolant to the anode, the coolant passages being arranged and constructed so that they can be made by machining and are free from soldered joints.
In plasma burners known from the state of the art coolant passages are made by means of opposing holes or counter-bores. These opposing holes subsequently have to be sealed to contain pressure, which is done by brazing. This is the reason why the known apparatus is made from brazable non-ferrous metals and has a correspondingly high weight. In apparatus known from the state of the art changes of material structure are caused by the soldering process, necessitating re-machining of the soldered joints. Re-machining is complicated by the fact that the soldered joints inside the coolant passages can only be accessed from outside with great difficulty. As the soldering flux is not fully controllable during the soldering process, solder flowing into the coolant passages may narrow their cross-sections of flow, particularly at critical points. This makes it necessary for such a plasma burner to be gauged to the through-flow of coolant after re-machining and cleaning of the soldered joints. The non-controllability and non-reproducibility of the soldering flux cause correspondingly high rejection rates in production. Apparatus known from the state of the art therefore requires a large outlay on manufacture and is correspondingly expensive.